1. Field of the Invention
The present invention relates to a magnetoresistance effect element using a magnetic layer having a non-magnetic metal matrix and fine magnetic particles dispersed in the matrix.
2. Description of the Related Art
A magnetoresistance effect element using a magnetoresistance effect is popularly used as a magnetic field sensor or a magnetic head. The magnetoresistance effect element formed by using a ferromagnetic material has excellent temperature stability and a wide temperature range in which the ferromagnetic material can be used. Conventionally, a permalloy thin film having a magnetoresistance ratio of about 2% is popularly used as the material of a magnetoresistance effect element using a magnetic material. However, the magnetoresistance ratio of the permalloy thin film is too small to obtain a sufficient sensitivity.
In contrast to this, in recent years, an artificial lattice film having a structure in which magnetic layers and non-magnetic layers are alternately stacked at a period of several .ANG. to several tens .ANG. and upper and lower magnetic layers are antiparallel-magnetically coupled to each other through a non-magnetic metal layer has received a great deal of attraction due to its great magnetoresistance effect. An artificial lattice film such as an (Fe/Cr).sub.n film (Phys. Rev. Lett., Vol. 61, p. 2,472 (1988)) or a (Co/Cu).sub.n film (J. Mag. Mag. Mat., Vol. 94, pL1 (1991)) has been developed. The great magnetoresistance effect is obtained scattering electrons depending on a spin direction of the magnetic layer.
It is most recently found that not only a multilayer but also a film having a Cu or Ag matrix and Co or Fe fine magnetic particles dispersed in the matrix has a large magnetoresistance effect (Phys. Rev. Lett. 68, 3749 (1992), Phys. Rev. Lett., 68, 3745 (1992), Phys. Rev., 46, 9266 (1992)).
The film in which the fine magnetic particles are dispersed can be easily formed compared with an artificial lattice film, and has an large MR ratio of about 20%. In addition, since the fine particles have small sizes and a single domain, an MR curve has no hysteresis. Therefore, when the film is used as a magnetoresistance effect element, it is expected that the magnetoresistance effect element has low Barkhausen noise. However, since a large magnetic field of 10 kOe or more must be applied to obtain a large MR ratio, this large magnetic field poses a problem in practical use.